Differential induction of human beta-defensin expression by periodontal commensals and pathogens in periodontal pocket epithelial cells.

BACKGROUND: To investigate the possible role of beta-defensins in gingival health and periodontal disease, we examined the effect of several stimuli on the expression of interleukin-8 (IL-8), human beta-defensin-1, -2, -3, and -4 (hBD) in primary human diseased gingival epithelial (HGE) cell cultures from periodontitis patients by quantitative TaqMan reverse transcription polymerase chain reaction (RT-PCR). METHODS: Several strains of the periodontopathogens Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were added to the cells, as well as the oral commensal bacteria Fusobacterium nucleatum and Escherichia coli. The induction by the proinflammatory stimuli phorbol 12-myristate 13-acetate (PMA) and tumor necrosis factor-alpha (TNF-alpha) was also tested. RESULTS: In addition to the published observations (PMA induces hBD-2 and -4; TNF-alpha induces hBD-2 and -3), it was found that PMA can upregulate hBD-1 and hBD-3, whereas TNF-alpha can induce hBD-4. The commensal bacteria were significant inducers of hBD-2, hBD-3, and IL-8. The pathogen P. gingivalis induced hBD-1 and hBD-3 at different time points than the commensals, but no induction of IL-8 and hBD-2 could be observed. These data fit with the chemokine paralysis theory. A correlation was found between the pathogenicity of different serotypes of A. actinomycetemcomitans and the induction profiles of defensins and IL-8. CONCLUSION: The results suggest that a correlation can be found in diseased oral epithelium between the defensin profiles that are induced and the pathogenicity of the oral bacterial strains.

Adhesion of Porphyromonas gingivalis serotypes to pocket epithelium.

BACKGROUND: Porphyromonas gingivalis, a key pathogen in periodontitis, is able to adhere to and invade the pocket epithelium. Different capsular antigens of P. gingivalis have been identified (K-serotyping). These P. gingivalis capsular types show differences in adhesion capacity to human cell lines or to cells cultured on a feeder layer or stromal equivalent. METHODS: The adhesion capacity of different P. gingivalis serotypes (6 capsular types and non-encapsulated strains) was compared on in vitro cultured epithelial monolayers from periodontal pockets of patients with periodontitis. The degree of adherence of P. gingivalis was evaluated by both culture and fluorescence microscopy. RESULTS: Non-encapsulated strains adhered significantly more than their capsulated variants. Capsule type 4 (K-4) adhered slightly better than the remaining K-types. CONCLUSION: This study indicates that the presence and type of capsule have a significant influence on the initial adhesion of P. gingivalis to human periodontal pocket epithelial cells.